fractional quantum Hall effect

Laughlin

...in 1998 for the discovery that electrons in an extremely powerful magnetic field can form a quantum fluid in which “portions” of electrons can be identified. This effect is known as the fractional quantum Hall effect.

Tsui

...for the discovery that the electrons in a powerful magnetic field at very low temperatures can form a quantum fluid whose particles have fractional electric charges. This effect is known as the fractional quantum Hall effect.